Table-Mounted Surgical Instrument Stabilizers

ABSTRACT

A surgical instrument stabilizer system that includes an articulating boom that is releasably connectable to a surgical table side rail. The articulating boom includes an actuator, a multi-directional flexible arm having a first end region attached to the actuator, and a cable extending through the flexible arm. The cable has one end region connected to the actuator and another end region connected to a preload tensioning mechanism. The actuator is operable to tighten and loosen the cable, and the preload tensioning mechanism maintains an amount of tension in the cable when the actuator loosens the cable. The system further includes a surgical instrument-supporting member that is attached to a second end region of the flexible arm and is configured to releasably retain a surgical instrument.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Application Ser. No.61/526,903, filed on Aug. 24, 2011, which is incorporated by referenceherein.

TECHNICAL FIELD

This invention relates to table-mounted surgical instrument stabilizers.

BACKGROUND

During surgery, whether open or laparoscopic, there is a need for adevice that can be utilized to stabilize surgical instruments forvarious functions, most commonly for stabilizing instruments that wouldotherwise be handheld, in order to achieve desired tissue tension or tomaintain exposure to the surgical site. Many such apparatuses alreadyexist.

SUMMARY

In one aspect of the invention, a surgical instrument stabilizer systemincludes an articulating boom that is releasably connectable to asurgical table side rail. The articulating boom includes an actuator, amulti-directional flexible arm having a first end region attached to theactuator, and a cable extending through the flexible arm. The cable hasone end region connected to the actuator and another end regionconnected to a preload tensioning mechanism. The actuator is operable totighten and loosen the cable, and the preload tensioning mechanismmaintains an amount of tension in the cable when the actuator loosensthe cable. The system further includes a surgical instrument-supportingmember attached to a second end region of the flexible arm. The surgicalinstrument is configured to releasably retain a surgical instrument.

Embodiments can include one or more of the following features.

In some embodiments, the flexible arm includes a plurality of nestinglinks, each of which has a hemispherical end region and a concave endregion. The hemispherical end regions of the nesting links matinglyengage the concave end regions of adjacent nesting links such that thenesting links are movable relative to one another.

In certain embodiments, a maximum diameter of the concave end region ofone of the nesting links is smaller than a maximum outer diameter of thehemispherical end region of another one of the nesting links that ismated with the concave end region of the one of the nesting links.

In some embodiments, average diameters of the nesting linksprogressively decrease in the direction of the surgicalinstrument-supporting member.

In certain embodiments, each of the plurality of nesting links has aninternal tubular member and an outer wall that concentrically surroundsthe internal tubular member, and the internal tubular member of each ofthe nesting links defines a lumen for passage of the cable.

In some embodiments, the outer wall defines the concave end region ineach of the nesting links.

In certain embodiments, the internal tubular member of each of thenesting links extends axially beyond the outer wall.

In some embodiments, the internal tubular member of each of the nestinglinks has a bottleneck configuration.

In certain embodiments, a first portion of the lumen extending along theconcave end region of each of the nesting links has a smaller diameterthan a second portion of the lumen extending along the hemispherical endregion of each of the nesting links.

In some embodiments, the second portion of the lumen of each of thenesting links receives therein a portion of the tubular member of anadjacent one of the nesting links.

In certain embodiments, the lumen and the tubular member of each of thenesting links are configured such that contact between the inner andouter walls, respectively, of adjacent nesting links limits rotations ofthe adjacent nesting links relative to one another.

In some embodiments, a contact angle at which a compressive force of oneof the nesting links contacts an adjacent one of the nesting links is18-30 degrees.

In certain embodiments, the lumen of each of the nesting links has afirst end, a central region, and a second end, and the lumen decreasesin diameter from the first end to the central region and increases indiameter from the central region to the second end.

In some embodiments, the internal members of the nesting links areshaped to maintain the cable centered within each of the nesting linkswhen the flexible arm is bent into a non-linear configuration.

In certain embodiments, the surgical instrument stabilizer systemfurther includes an elastic grommet disposed within the lumen of each ofthe nesting links.

In some embodiments, the preload tensioning mechanism includes acompression spring mounted on an anchor that is attached to the cable.

In certain embodiments, the anchor includes a bulbous head, and thecompression spring is mounted between the bulbous head of the anchor anda surface of the surgical instrument-supporting member.

In some embodiments, the compression spring is biased to move the anchorand the cable away from the surface of the surgicalinstrument-supporting member.

In certain embodiments, the surgical instrument-supporting memberincludes a collar, and the surface of the surgical instrument-supportingmember is an internal surface of the collar.

In some embodiments, the collar is configured to permit rotation of thesurgical instrument-supporting member relative to the flexible arm.

In certain embodiments, the surgical instrument stabilizer systemfurther includes a rigid arm assembly that supports the articulatingboom and that is attached to a side rail of a surgical table by aclamping assembly in a manner such that the rigid arm assembly and thearticulating boom can be slid along the side rail.

In some embodiments, the surgical instrument stabilizer system furtherincludes a locking ball coupling that connects the rigid arm assembly tothe articulating boom, and the locking ball coupling carries thearticulating boom at the center of gravity of the articulating boom.

In certain embodiments, the surgical instrument stabilizer systemfurther includes a surgical instrument that is secured in theinstrument-supporting member and can be repositioned and locked in adesired position and orientation single-handedly.

Embodiments can include one or more of the following advantages.

In some embodiments, the stabilizer system serves to securely hold anyof various different instruments during any of various differentprocedures, for example, during laparoscopic sacral colpopexy whichrequires a stable probe during suturing of mesh to the vagina. Thesystem is portable and may be attached anywhere around the opposingside-rails and/or head/foot rails mounted along an existing surgicaltable to provide a combination of different adjustment capabilities,effectively allowing a surgeon to manually position and then stabilizean instrument anywhere above and around the table at any orientation, ondemand. In some cases, the instrument can be operated using only onehand or by voice activation.

In certain embodiments, a first range of unidirectional positioning isachieved with a flexible arm connected to an instrument-supporting handpiece, the arm allowing the handpiece to be positioned anywhere and atany orientation within reach of the arm, and the arm “frozen” to lockthe instrument in that position. A second range of unidirectionalpositioning is achieved by mounting the flexible arm in an articulatingbase that includes a locking ball joint. The arm may be reorientedanywhere within a hemispherical range of motion about ball joint andlocked in position. Moreover, the articulating base is suspended from aclamping assembly that may be clamped to the rails of a conventionalsurgical table anywhere around the table. Consequently, a third range ofunidirectional positioning is achieved by translating the clampingassembly around the table. Lastly, a fourth range of motion is achievedby the instrument-supporting hand piece (at the end of the flexiblearm), which is pivotal for angular orientation of the instrumentsupported thereby.

Thus, in some embodiments, the system allows easy single handed (orvoice activated) repositioning in multiple directions (any direction,rotation or angle) when in an “unlocked” condition, a secure fixedposition when in a “locked” condition, and with variable user-adjustableresistance there between, coupled with same hand (or voice activated)control over the rigidity of the flexible arm combined with the deliveryof vacuum when applicable.

In certain implementations, the flexible arm of the systems isconfigured to minimize or eliminate hand piece shifting or drift, andimprove the stability of a surgical instrument (e.g., vaginal probe)being supported thereby.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary embodiment of a stabilizersystem.

FIG. 2 is a side view of another embodiment of a stabilizer systemsimilar to FIG. 1 with an additional (optional) ball joint.

FIG. 3 is an end view of the stabilizer system shown in FIG. 2.

FIG. 4 is a perspective view of a quick-release clamping assembly of thestabilizer systems of FIGS. 1-3.

FIG. 5 is a side view of the quick-release clamping assembly of FIG. 4.

FIG. 6 illustrates a flexible arm used in the stabilizer systems ofFIGS. 1-3, with enlarged insets to provide more detailed views ofcertain features of the flexible arm.

FIG. 7 is a graph of the moment-carrying capability (ft-lbs) of twolinks of the flexible arm shown in FIG. 6, as a function of a contactangle Θ (degrees offset from horizontal).

FIG. 8 is an enlarged side-view of a hand piece, that is carrying avaginal probe and is supported by the flexible arm of the stabilizersystems of FIGS. 1-3.

DETAILED DESCRIPTION

FIG. 1 is a side perspective view of an exemplary embodiment of thestabilizer system 1. The stabilizer system 1 is portable and attaches tothe existing horizontal side and end-rails 12 mounted to the opposingsides and ends of most surgical tables 13. The rails 12 are typicallymounted on spacers so as to space them approximately 1″ outward from thetable 13. Many surgical tables in the United States employ standardizedNorth American rails, which are well suited for present purposes. Aquick-release clamping assembly 50 can be attached anywhere along therails 12 for supporting the entire stabilizer system 1 therefrom. Thequick-release clamping assembly 50 hooks overtop the rail 12 and clampsvia a pair of lever arms 52 that bear against the bottom of the rail 12,allowing them to manually clamp assembly 50 about the rail 12 forsupporting the entire stabilizer system 1 therefrom. The quick-releaseclamping assembly 50 suspends a ball coupling 67 including a short linkhaving a ball at the distal end. The ball of coupling 67 is pivotallyinserted into a base 65, and specifically into a locking receptacle 68of base 65 thereby forming a first locking ball-and-socket pivot joint.The other end of ball coupling 67 may be fixedly secured toquick-release clamping assembly 50, as shown in FIG. 1, or as shownbelow with reference to FIG. 2, may be pivotally attached toquick-release clamping assembly 50 by a second locking ball-and-socketpivot joint. The base 65 carries an articulating boom including anactuator 64 mounted inside actuator housing 54. The actuator housing 54may be integral to base 65 as shown and contains a servo motor or othersuitable actuator. Base 65 extends to a flexible arm 22 mounted thereto.The ball coupling 67 suspends the entire articulating boom at anydesired orientation within a hemispherical range of motion vis a vis theorientation of its ball inside the locking receptacle 68 of base 65, andthe orientation of ball coupling 67 may be adjusted by unlockingreceptacle 68 of base 65, adjusting, and then clamping it in placeagain.

FIG. 2 is a side view of a similar embodiment of the stabilizer system1. In this embodiment, the stabilizer system 1 includes an additional(optional) ball joint 62 beneath the clamping assembly 50. Thequick-release clamping assembly 50 suspends the ball-hitch mechanism 62downward from the rail 12. The ball-hitch mechanism 62 includes alocking ball-in-socket receptacle 58 fixedly attached to thequick-release clamping assembly 50, and a dogbone ball coupling 67including a short link having a ball coupling at both ends. One end ofdogbone ball coupling 67 is pivotally inserted into the ball-hitchmechanism 54 thereby forming a first locking ball-and-socket pivotjoint. The other end of dogbone ball coupling 67 is pivotally clamped ina base 65 thereby forming a second locking ball-and-socket pivot joint.The ball coupling 67 can at any of various different orientations fromthe ball-hitch mechanism 62 into a locking receptacle 68 of base 65, andthe orientation of ball coupling 67 may be adjusted within ahemispherical range of motion by unlocking ball-in-socket receptacle 58,adjusting, and then clamping it in place again. The ball-hitch mechanism62 is essentially a heavy-duty camera tripod head as shown in the insetof FIG. 2, with a manual lock-screw.

In operation, the locking receptacle 68 of base 65 provides the entirearticulating boom with unidirectional positioning capability around alarge number of different axes, and the (optional) suspended ball-hitchmechanism 62 of FIG. 2 extends the range of motion. In effect, theclamping assembly 50 may be clamped anywhere around the rails 12 ofconventional surgical table 13, thereby providing a first range ofpositioning around a horizontal rectangular plane. A second range ofunidirectional positioning is achieved by suspending the boom andflexible arm 22 from a fulcrum at the ball coupling 67 (and atball-hitch mechanism 62 if included). The arm 22 may be reorientedanywhere within a hemispherical range of motion and locked in position.FIG. 3 is an end view of the stabilizer system 1 as in FIG. 2 with anenlarged inset of the locking receptacle 68. The locking receptacle 68includes two-opposed half-cup-shaped members, one fixed and onetranslatable along base 65. The ball coupling 67 extends transverselyfrom the clamping assembly 50 into the locking receptacle 68 of base 65,and the cooperating halves of the locking receptacle 68 operate in avice-like manner to selectively lock/release the ball coupling 67 inposition. Drawing the cup-shaped members together clamps the ballcoupling 67 in a stationary position, and the mechanism for doing thismay be any suitable internal gearing or electric or pneumatic means.Releasing pressure from the cup-shaped members unclamps the ballcoupling 67 for free pivoting, but does not initially allow release ofthe boom. If desired, the failsafe position of the cup-shaped members ofthe locking receptacle 68 may be further separated for full removal ofthe boom from the clamping assembly 50.

The ball coupling 67 typically extends into the base 65 at or very nearthe center of gravity of the entire articulating boom. As a result, whenthe physician unclamps the locking receptacle 68, the articulating boomdoes not pivot wildly.

With reference to FIGS. 4 and 5, the quick-release clamping assembly 50may be clamped anywhere around the rails of a conventional surgicaltable. The quick-release clamping assembly 50 includes a plate member 51that extends upward to a hooked upper edge 53. The hooked upper edge 53hooks overtop the rail 12 in a tongue-and-groove manner. The lever arms52 are pivotally mounted to the plate member 51 and when pivotedtogether to the position shown in FIG. 4, they conform to the rail 12and bias it tight from beneath, likewise in a tongue-and-groove manner.If desired, roller(s) or pads can be provided along the upper bearingsurfaces of lever arms 52 to reduce friction against the side rails 12when clamping tight. Either way, the lever arms 52 effectively clamptight to the rail 12, allowing it to support the entire stabilizersystem 1. Beneath the lever arms 52 the plate member 51 extends downwardto a support member defined as a reverse-L-shaped member having avertical portion and inwardly-turned horizontal flange 55, and a centralnotch 56 running a majority of the length of the vertical portion andinwardly-turned horizontal flange 55, bisecting the support member intotwo opposed sides 54. The ball coupling 67 (or ball-hitch mechanism 62)may be bolted anywhere along the notch 56 to plate member 51, therebyallowing a vertical-downward or horizontal-outward orientation of theball-hitch mechanism 62.

Referring back to FIG. 1, the flexible arm 22 continues to a hand piece60 within which a surgical instrument such as a probe 70 is mounted. Theflexible arm 22 includes a plurality of mating ball and socket links 230optionally covered with a thin walled elastomeric sheath (not shown).The sheath is intended to improve sterilization capabilities and improvethe aesthetics.

A tensioning cable 240 (described below) runs throughout the arm 22 andbase 65 to actuator 64 where it connects thereto by a pulley or othersuitable mechanism, the actuator 64 controlling the tension load on thecable 240. As the cable 240 tension is increased, the links 230 endure acorresponding increase in compressive load between each mating ball andsocket. This loading system creates normal force loads between the balland socket links 230, which in turn generates friction loads. As loadson each link 230 are increased (with higher tension in the cable 240),each link 230 imposes higher friction forces, which collectively altersthe overall flexibility of the arm 22. Thus, at higher cable 240tension, the arm 22 will endure external loads such as a surgeonpressing on a given tool (such as probe 70) that is being supported bythe system 1. Therefore, greater tension in the cable 240 allows the arm22 to support higher loads at the end of the arm 22 that supports agiven tool, due to the increased friction between the links 230. At lowcable 240 tension, there is little friction between the links 230 andthe arm 22 can be manually moved and positioned by the operator withlittle resistance. Thus, the stiffness of the arm 22 and hence theamount of friction between links 230 is important, and this is afunction of a number of variables including the geometry of the links230, materials, mating surface finishes, and the magnitude of the normalforce on each link.

It is essential for certain procedures that the arm 22, once locked inposition, minimizes or eliminates hand piece 60 drift which can affectthe stability of the probe 70 or other instrument being supportedthereby. It is also desirable to accomplish the foregoing with minimumcable 240 tension, so as to reduce the necessary power requirements ofthe tensioning actuator 64. The preferred links 230 accomplish this witha particular geometry, size, materials and surface finish which aredescribed in detail below. The movement of the cable 240 by actuator 64(and hence the tension in the cable 240) may be controlled in variousways. For example, the tension in the cable can be controlled by abutton 222 mounted on the instrument-supporting hand piece 60, whichbutton 222 may be connected to actuator 64 via a hard wired connection,optical, infrared, RF, Bluetooth (or other wireless communication). Whenused with a hard wired or optical connection, a slip ring or rotatingconnector collar 224 (see FIG. 5) is preferably incorporated at the baseof the hand piece 60 to allow the wires or optical fibers to sliprelative to the mating link 230 and therefore prevent damage to thewires or fibers that could occur when the hand piece 60 is over rotatedby the operator relative to the actuator 64.

Alternatively, button 222 may be replaced with a foot pedal controllerin communication with the actuator 64. Button 222 may also be replacedwith a voice activated control system in communication with the actuator64. A suitable voice activated control system includes a microphonecoupled to an audio amplifier in turn coupled to a processor capable ofrunning voice recognition software, such as Dragon Naturally Speaking™software commercially available from Nuance™, or Fonix FAAST™ softwarecommercially available from Fonix Corporation, 1225 Eagle Gate Tower, 60East South Temple, Salt Lake City, Utah.

The processor may be the actuator 64 control system. Button 222 (or footpedal or voice control) provides for convenient same hand (orvoice)-operated control over the amount of flex imparted to the arm 22.Pressing the button 222 or foot pedal (and holding it in thisorientation), causes the cable 240 in the actuator 64 to extend or growin length which reduces the amount of tension in the cable 240 by apredetermined amount and thereby reduces the friction load between thelinks 230 such that the flexible arm 22 can move in a more relaxedmanner as chosen by the operator. Releasing the button 222 causes thecable 240 in the actuator 64 to retract in overall length whichincreases the amount of tension in the cable 240 by a predeterminedamount, thereby increasing the friction load between the links 230 suchthat the flexible arm 22 has increased rigidity to a selectable degreechosen by the operator. At maximum tension the arm 22 becomes fullyrigid in that the links 230 will not rotate relative to each otherunless the maximum loading of the arm 22 is exceeded.

In the case of voice activation, the operator will be able to controlthe movement and location of the flexible arm 22 through oral messagesinterpreted by an on-board processor such as the actuator 64 controlsystem.

Hand piece 60 is an ergonomic instrument-supporting receptacle mountedto the distal end of the flexible arm 22, and the hand piece 60 acceptsa variety of probe-adapter inserts 220 each of which serves as aconforming receptacle for insertion of a probe 70 or other instrument.In the illustrated embodiment of FIG. 1, a vaginal probe 70 is mountedin the probe-adapter insert 220 on the instrument-supporting hand piece60. Although, it should be understood that most any instrument orimaging device may be so mounted with a conforming probe-adapter insert220.

In some embodiments, the system 1 can: 1) allow easy single handed (orvoice control) repositioning of the arm 22 in multiple directions (anydirection, rotation or angle) when in an unloaded or “unlocked”condition; 2) provide a secure fixed position when in a “locked”condition; and 3) provide the user with variable user-adjustableresistance there between, coupled with single-hand or voiceactivated-control over the rigidity of the flexible arm 22. This wouldbe well-suited for situations requiring frequent repositioning, such asfor stabilization of a laparoscopic camera, and would be equally suitedfor stabilizing a rectal probe, uterine manipulator, vaginal probe 70 orsimilar surgical tools. The need for adjustable resistance arises fromthe different types of instruments requiring stabilization. Forinstance, a table mounted stabilizer used to hold a laparoscopic camerain a fixed position requires only minimal resistance because it needonly resist the weight of the camera itself. In contrast, a stabilizerused to hold a vaginal probe used during laparoscopic sacral colpopexyor a uterine manipulator during laparoscopic hysterectomy would requiresubstantially greater resistance in order to keep the probe stableduring suturing of mesh to the vagina. The present inventionaccomplishes this by including the ability to adjust the overall tensionin the cable 240.

The system provides multiple features for “on-the-fly” adjustment of thelocation and operating range of the flexible arm 22 via four primarysurgeon-effected adjustments settings A thru D as described below (withreference to FIG. 1):

At point A, the instrument-supporting hand piece 60 is pivotally mountedto the distal end of the flexible arm 22 for angular orientation of theinstrument supported thereby.

Point B is the omnidirectional adjustment and articulation implementedby the flexible arm 22 for local positioning (controlled by button 222or foot pedal or voice) with internal tensioning cable 240 (allowingmulti-axis positioning by the plurality of ball and socket links 230).

Point C (ball coupling 67 in locking receptacle 68) allows sphericalglobal positioning of both the flexible arm 22 and instrument-supportinghand piece 60. This is accomplished by releasing the locking receptacle68 to unlock and pivot the ball coupling 67, and relocking

Finally, Point D allows global lengthwise positioning of the entire boomincluding flexible arm 22, instrument-supporting hand piece 60, actuator64, and clamping assembly 50 along the surgical table 13 by virtue ofthe quick-release clamping assembly 50, which is movably mounted to theside-rails 12. The foregoing configuration facilitates easy local andglobal multi-directional repositioning of the supported instrument andvariable resistance-setting. The range of motion is significantlyincreased by this combination. Surgical instruments can be supported inany location and any orientation within a 60 centimeter diameterspherical range of the point of origin of the instrument-supporting handpiece 60.

Moreover, as described more fully below, the selection parameters of thematerial used for the flexible elements 230 (e.g., high modulus ofelasticity), combined with manufacturing requirements for controlled anduniform surface finish (e.g., injection molding) as well as the designof the optimum geometry of the flexible elements 230 has enabled theload carrying capacity of the foregoing configuration to besubstantially greater than prior art stabilizers.

As indicated above, the flexible arm 22 includes a plurality of links230, optionally covered with a thin walled elastomeric sheath. FIG. 6illustrates the presently-preferred flexible arm configuration whichgenerally includes an end adapter 210 at one end for insertion into theactuator housing 54, and a hand piece 60 at the other end for mountingthe desired surgical tool that needs to be stabilized, a plurality ofball-and-socket links 230 there between, and a tensioning cable 240anchored in the collar 224 and running throughout the ball-and-socketlinks 230, end adapter 210 and actuator housing 54, and engaged to theactuator 64 for selectively tensioning or releasing ball-and-socketlinks 230. The cable 240 is attached at one end to the actuator 64 andat the other end to collar 224 which serves as an anchor for the cable240 terminus. The ergonomic instrument-supporting hand piece 60 ismounted at the distal end of the flexible arm 22, and the hand piece 60accepts a variety of surgical tool adapters 220 as described above eachof which is fitted to serve as a receptacle for insertion of a surgicaltool, such as the vaginal probe 70, a camera, a cutting instrument, etc.If desired (though not shown), ball-and-socket links 230 may be coveredwith a thin walled elastomeric sheath end-to-end for aesthetics andpossible cleaning and sterilization improvement issues. The tensioningcable 240 may be any suitable twisted fiber cord or cable. Typically, ⅛″stainless steel wire rope is used to form the tensioning cable 240. Thecable 240 runs throughout the links 230 of the arm 22 and through theactuator housing 54 to the motor pulley (or actuator cylinder) inactuator 64, and in this way the actuator 64 can gradually pull(tension) the cable 240, which compresses the links 230 together toincrease their collective rigidity, and ultimately lock them inposition. The primary parameters of the flexible arm 22 are its abilityto articulate mechanically in any direction, electrically ormechanically freeze a desired position along its entire length, and holdthat position with maximum strength and rigidity. The flexible arm 22typically does this with between 5 and 50 ball-and-socket links 230configured as shown.

Several design features for these links 230 are described below whichwere developed to optimize the performance of the system 1. Shifting ofthe distal end of the arm 22 when placed under load is highlyundesirable since the arm must securely hold and position precisionsurgical tools, cutting instruments, probes and/or cameras. Unexpectedshifting can, in certain cases, cause injury to the patient orcomplications for the user. It is desired for present purposes that thearm 22, once locked in position, minimizes or eliminates hand piece 60shifting (“drift”) which can affect the stability of the probe 70 beingsupported thereby. It is also desirable to accomplish the foregoing withminimal cable 24 tension, so as to reduce the necessary power of thetensioning drive system. The stiffness of the arm 22 is a function of anumber of variables including the geometry of the links 230 (e.g., thesize of the links 230), the materials of the links 230, the matingsurface finishes, and the magnitude of the normal force on each link.The preferred geometry, size, materials and surface finish of the links230 for accomplishing this follow.

Materials

The optimal material for links 230 will have a high static and slidingcoefficient of friction. Typically, the static frictional coefficientwill be in excess of 0.7 and the sliding coefficient of friction willexceed 0.5. Examples of suitable materials include Ultem® PolyEtherlmide(“PEI”) which is a high performance polymer with static/slidingcoefficients of friction of 0.8, plus excellent dimensional stabilitycombined with chemical resistance, and aluminum which exhibits improvedmaterial properties and even higher coefficients of frictions (1.05-1.35static, 1.4 sliding).

Geometry of Links

As seen in the insets to FIG. 6, the links 230 have a ball-and-socketdesign, with a convex partial-spheric face or dome 233 at one end and aconcave partial-spheric face or recess 231 at the other end. Each convexdome 233 on one link conforms to the concave recess 231 on the adjoininglink. The ball-and-socket links 230 nest end-to-end and are capable oflimiting relative pivoting. The spherical diameter of the concave end231 is purposefully designed to be slightly smaller than the matingconvex end 233. This concentrates a portion of the reaction load along acircular line formed between the two mating spherical parts. This inturn increases the normal force along a circular line of contact,thereby increasing the friction loads and the moment carrying loadcapacity of the joint by maintaining an optimal friction loadinggeometry in each link. Each link 230 typically has a convexpartial-spherical face 233 with a maximum diameter of about 1.5 inches,and within a range of from 0.5 to 4 inches, leading to a pronouncedbell-shaped lip 232. The concave end 231 is typically sized to be 0.006inches smaller in diameter than the convex part, although othercombinations of material properties and sizes could also be used toachieve some measure of this feature. It is understood that the flexiblearm 22 and the boom as a whole should be as lightweight as possible, andso the links 230 are typically as small as possible.

Moreover, when a load is applied to the probe 70, the moment loadthroughout the flexible neck 22 increases with distance from the appliedload. Consequently, the size of the links 230 toward the probe 70 neednot be as large as those toward the base 65. Therefore, in someembodiments, the links 230 progressively increase in diameter/weightproximally toward the base 65.

The geometry of the links can ensure that adjacent links 230 contacteach other at the appropriate contact angle Θ, as shown in FIG. 6 inset(top right). The moment-carrying capability (and hence anti-slipresistance) of the flexible arm 22 is a function of the contact angle Θ,i.e., the angle at which the compressive force of a link 230 contactsthe next adjacent link, measured as an offset from horizontal. Themoment-carrying capability can be calculated using the followingequations.

$\begin{matrix}{F_{N} = \frac{T}{\sin (\theta)}} & {{Normal}\mspace{14mu} {force}\mspace{14mu} {on}\mspace{14mu} {ball}\mspace{14mu} {surface}} \\{F_{T} = {\mu \cdot F_{N}}} & {{Tangential}\mspace{14mu} {force}\mspace{14mu} {on}\mspace{14mu} {ball}\mspace{14mu} {surface}}\end{matrix}$

Moment Carrying Capability of Link

$M = {2 \cdot {\int_{0}^{\pi}{{\frac{F_{T}}{2 \cdot \pi} \cdot \lbrack {{{R \cdot \sin}\; (\theta)} + {( {R - {R \cdot {\sin (\theta)}}} ) \cdot {\sin (\varphi)}}} \rbrack}{\varphi}}}}$φ = angle  in  hoop  direction$M = {{\frac{F_{T} \cdot R}{\pi} \cdot \lbrack {2 + {( {\pi - 2} ) \cdot {\sin (\theta)}}} \rbrack} = {\frac{\mu \cdot F_{N} \cdot R}{\pi} \cdot \lbrack {2 + {( {\pi - 2} ) \cdot {\sin (\theta)}}} \rbrack}}$

FIG. 7 is a graph of the moment-carrying capability (ft-lbs) of twolinks 230 as a function of the contact angle Θ (degrees offset fromhorizontal). As the contact angle Θ increases, the moment-carryingcapability exponentially decreases, and so the contact angle Θ ispreferably minimized. On the other hand, if contact angle Θ falls belowa minimum of approximately 18 degrees for aluminum material, the links230 are prone to sticking Applicant's research indicates that optimumcontact angle Θ is approximately 20 degrees for aluminum, within anacceptable range of from 18-30 degrees. Consequently, each convex dome233 on one link is dimensioned to conform to the concave recess 231 onthe adjoining link accordingly, resulting in an ideal interfaceorientation between links 230 to maximize holding capacity of the linkswhile minimizing the necessary cable tension load.

The convex partial-spherical face 233 of each link 230 is defined by anaperture 234 for cable 240 passage, and the cable passage continuesthrough the link 230 through a tubular member 236 which traverses thelink 230 exiting through the concave end 231 and protruding a shortlength there beyond. The tubular member 236 nests adjacent links 230 andlimits over-rotation of the links 230 while also maintainingconcentricity with the cable 240. All three of these can be importantfactors. Specifically, the tubular member 236 maintains a nested matingrelationship between adjacent links 230 and limits over-rotation,thereby ensuring that the plurality of links 230 define a smooth overallcurvature (eliminating localized kinks in the arm 22). This ensuressmoother operation of the link system when not under actuation load, andprevents individual links 230 from randomly cocking on the cable 240. Ithas been found that if adjacent links 230 over rotate off theirspherical face 233 their behavior becomes unpredictable, and the tubularmember 236 prevents this. Moreover, the tubular member 236 as well asthe internal geometry of the tubular member 236 act as a cable guide toensure that the cable 240 maintains a smooth overall curvature inside.If the cable routing is eccentric the flexible arm 22 will kick in adirection upon cable loading. The tubular member 236 guides the cable inclose concentricity through the links 230 and maintains a uniformcurvature of the cable 240 through links 230. Further toward this end,it can be seen that the internal walls of the tubular member 236 arecontoured lengthwise to essentially define a bottleneck, more open atthe convex end 233, constricted about two-thirds of the length towardthe concave end 231, and opening outward slightly at the concave end231. The bottleneck configuration of the inner walls of tubular member236 guide the cable through each link 230 in a uniform arcuate pathdirectly through the center of the links 230, and ensures that the cable240 maintains the same concentric-curvilinear path from link 230 to link230. The net result is a uniform cable curvature in close concentricitythroughout the entire flexible arm 22, which assures uniform compressionof all the links 230 and avoids any preferential compression between anytwo links 230. Otherwise, given that the cable may experience in excessof 1000 lbs of tension, the configuration described preventseccentricity which promotes preferential compression on one side orother, thereby avoiding movement, kicking or shifting of the arm 22 toone side.

In practice, the cable terminus will typically be equipped with a swagefitting that is inserted through the links 230 during manufacturing, andthis constraint compels a slightly larger lumen through the tubularmembers 236 to accommodate the swage fitting. This would otherwisedetract from the need for close concentricity of the cable and couldpromote preferential forces, rubbing and abrasion. To alleviate this, itis envisioned that the interior walls of the tubular members 236 mayinclude a flexible (rubberized) grommet-like insert that expands toallow for passage of the cable swage fitting (during initial assembly)that then closes around the cable to maintain concentricity. In caseswhere the cable terminus can be swaged on after the cable has beenpassed through the links it is possible to keep the lumen sufficientlysmall to illuminate the need for a grommet or similar insert.

Another design feature is related to the surface finish and materialtype, each of which can affect the friction coefficient between themating links 230. It is desirable to achieve a relatively highcoefficient of friction between the mating links 230 to increase theload holding capacity of the flexible arm 22. It can be advantageous toachieve a friction coefficient greater than 1.0. In this regard it maybe desirable to form the convex surface 233 of each link 230 with agranular or otherwise defined matte surface finish to boost the frictioncoefficient.

The combination of the high modulus of elasticity material used for thelinks 230, high coefficient of friction between the mating links 230(e.g., increased by controlled and uniform injection-molded surfacefinish), as well as the above-described optimum geometry of the links230, has enabled the load carrying capacity of the above-describedconfiguration to be substantially greater than many prior artstabilizers. Specifically, once the arm 22 is locked, the table mountedstabilizer system has a minimum load carrying capability of 2 ft-lbstorsionally, 25 pounds axially and 10 pounds laterally for rigid,reliable and secure support of an instrument.

The axial passage 234 through the tubular member 236 of each link 230passes the cable 240, and a control wire to the button 222, and(optionally) provides a passage for the delivery of negative airpressure (vacuum) for suction instruments. The end adapter 210 includesa square insert 212 backed by a flange 212 at one end for insertion intoa square tubular receptacle in the base 65. Another ball-and-socket linkidentical to 230 protrudes integrally from the other side of flange 212,albeit no inner tubular member 236 is required. The hand piece 60typically allows rotation via connector collar 224 (see FIG. 5) andadapter 220 typically allows hemispherical pivoting of the instrument 70wielded thereby. The ergonomic hand piece 60 is a contoured memberhaving the arm control button 222 mounted there atop. The throw ofactuator 64 is controlled by the button 222 on the instrument-supportinghand piece 60. The hand piece 60 includes an open-ended receptacle forinsertion of one of a variety of adapters 220 that will interface withand support a variety of desired surgical tools. The adapter 220typically allows snap-fit insertion of a vaginal probe 70 or otherdevice. A bayonet type connection (or similar twist locking style ofconnection) is also a suitable alternative.

The actuator 64 can be a variety of different types. For example, theactuator 64 may be an electronic motor that selectively winds/unwinds atensioning cable onto a pulley. Alternatively, the actuator 64 may be alinear actuator, or pneumatic cylinder (e.g., air cylinder), hydrauliccylinder, or any other suitable actuator capable of tightening/looseninga cable. The actuator 64 provides the motive force and incorporatescontrol circuitry in actuator housing 54 to selectively tighten/loosenthe internal tensioning cable 240 which extends through actuator housing54 to the flexible arm 22 mounted there atop. Typically, actuator 64includes an internal actuator control system constructed according tothe type of actuation, and generically including one or more position orload sensors, a PLC controller, and hydraulic/pneumatic valves asnecessary. By way of example, Duff-Norton™ sells a TracMaster™ line oflinear actuators in a variety of stroke lengths, along with accessorycontrol packages and digital position and load indicators that willsuffice.

FIG. 8 is an enlarged side-view of the flexible arm 20 supporting thehand piece 60, which is in turn carrying a vaginal probe 70. Theprobe-adapter inserts 220 may assume various internal configurations asneeded for snap-fit insertion or bayonet locking and secure holding ofany of a variety of surgical tools (such as vaginal probe 70, orsurgical tools, cutting instruments, cameras or the like). Thiseffectively makes the table mounted stabilizer system 1 universallycapable of holding most any instrument, universally capable ofmanipulating that instrument into any desired position and angle, andthen locking it in fixed position. In many cases, the manipulation andlocking of the instrument can be carried out with a single hand (oroptional voice activated control) by a surgeon or surgical assistant.

One additional feature of the arm 22 helps to minimize or eliminate handpiece shifting or drift, and improve the stability of the probe 70 beingsupported thereby. The entire flexible neck 22 is tensioned by a preloadtensioning mechanism at the hand piece 60. Applicants have found that assmall as a 0.0001″ gap between adjacent links 230 can cause the cable tokick and/or and start rubbing. The preload tensioning mechanismeliminates gaps between the links 230 and the end supports, whichreduces tool drift (motion) during cable 240 actuation. The preloadtensioning mechanism is shown in the inset of FIG. 8 and is incorporatedinto the cable 240 terminus in collar 224. The tensioning cable 240continues down throughout the arm 22, base 65 and actuator housing 54and connects to actuator 64, the actuator 64 controlling the tensionload on the cable 240. The collar 224 is defined by an interior chamber228 at the probe 70 end, and a metallic anchor 227 is seated inside thechamber 228. The cable 240 passes into the collar 224 through the anchor227 and (typically the cable's swage fitting) is anchored thereto on theother side. The anchor 227 is allowed a limited amount of axial float,e.g., a degree of freedom to slide along its axis, and the preloadtensioning mechanism imparts a pre-bias to the cable vis-á-vis theanchor 227. This is accomplished by forming the anchor 227 as acylindrical stem leading to a bulbous head. A washer 226 is fitted tothe stem and abuts the head, and a compression spring 229 is mounted onthe anchor 227 stem between the head and interior wall of collar 224.

When no tension is applied to the cable 240 by the actuator 64 any cableextension within collar 224 is absorbed by the floating anchor 227 andcompression spring 229, which effectively maintains a predeterminedpre-bias on the next adjacent link 230 despite unlocking of the flexiblearm 22 as seen in the FIG. 8 inset at (A). Conversely, when tension isapplied to the cable 240 by the actuator 64 the cable retraction withincollar 224 overcomes the compression spring 229, which becomesinoperative as seen in the FIG. 8 inset at (B). Again, as the cable 240tension is increased the links 230 endure a corresponding increase incompressive load between each mating ball and socket. With thetensioning mechanism, when the cable 240 tension is released the links230 will relax to a predetermined minimum compressive load between eachmating ball and socket, imparted by compression spring 229. This againhelps to minimize or eliminate hand piece shifting or drift, and improvethe stability of the probe 70 being supported thereby.

One skilled in the art should now understand that the foregoing allowsfull adjustability of the location of the desired instrument up and downalong a vertical axis, forward and back, i.e, toward or away from thepatient, and rotationally so that the desired instrument can be angledup or down and side to side. Once locked the table mounted stabilizersystem has a minimum load carrying capability of 2 ft-lbs torsionally,25 pounds axially and 10 pounds laterally for rigid, reliable and securesupport of any device.

Other embodiments are within the scope of the following claims.

1. A surgical instrument stabilizer system comprising: an articulatingboom that is releasably connectable to a surgical table side rail, thearticulating boom comprising an actuator, a multi-directional flexiblearm having a first end region attached to the actuator, and a cableextending through the flexible arm, the cable having one end regionconnected to the actuator and another end region connected to a preloadtensioning mechanism, the actuator being operable to tighten and loosenthe cable, and the preload tensioning mechanism maintaining an amount oftension in the cable when the actuator loosens the cable; and a surgicalinstrument-supporting member attached to a second end region of theflexible arm, the surgical instrument being configured to releasablyretain a surgical instrument.
 2. The surgical instrument stabilizersystem according to claim 1, wherein the flexible arm comprises aplurality of nesting links, each of the nesting links having ahemispherical end region and a concave end region, wherein thehemispherical end regions of the nesting links matingly engage theconcave end regions of adjacent nesting links such that the nestinglinks are movable relative to one another.
 3. The surgical instrumentstabilizer system according to claim 2, wherein a maximum diameter ofthe concave end region of one of the nesting links is smaller than amaximum outer diameter of the hemispherical end region of another one ofthe nesting links that is mated with the concave end region of the oneof the nesting links.
 4. The surgical instrument stabilizer systemaccording to claim 2, wherein average diameters of the nesting linksprogressively decrease in the direction of the surgicalinstrument-supporting member.
 5. The surgical instrument stabilizersystem according to claim 2, wherein each of the plurality of nestinglinks has an internal tubular member and an outer wall thatconcentrically surrounds the internal tubular member, the internaltubular member of each of the nesting links defining a lumen for passageof the cable.
 6. The surgical instrument stabilizer system according toclaim 5, wherein the outer wall defines the concave end region in eachof the nesting links.
 7. The surgical instrument stabilizer systemaccording to claim 5, wherein the internal tubular member of each of thenesting links extends axially beyond the outer wall.
 8. The surgicalinstrument stabilizer system according to claim 5, wherein the internaltubular member of each of the nesting links has a bottleneckconfiguration.
 9. The surgical instrument stabilizer system according toclaim 5, wherein a first portion of the lumen extending along theconcave end region of each of the nesting links has a smaller diameterthan a second portion of the lumen extending along the hemispherical endregion of each of the nesting links.
 10. The surgical instrumentstabilizer system according to claim 9, wherein the second portion ofthe lumen of each of the nesting links receives therein a portion of thetubular member of an adjacent one of the nesting links.
 11. The surgicalinstrument stabilizer system according to claim 10, wherein the lumenand the tubular member of each of the nesting links are configured suchthat contact between the inner and outer walls, respectively, ofadjacent nesting links limits rotations of the adjacent nesting linksrelative to one another.
 12. The surgical instrument stabilizer systemaccording to claim 11, wherein a contact angle at which a compressiveforce of one of the nesting links contacts an adjacent one of thenesting links is 18-30 degrees.
 13. The surgical instrument stabilizersystem according to claim 5, wherein the lumen of each of the nestinglinks has a first end, a central region, and a second end, and the lumendecreases in diameter from the first end to the central region andincreases in diameter from the central region to the second end.
 14. Thesurgical instrument stabilizer system according to claim 5, wherein theinternal members of the nesting links are shaped to maintain the cablecentered within each of the nesting links when the flexible arm is bentinto a non-linear configuration.
 15. The surgical instrument stabilizersystem according to claim 5, further comprising an elastic grommetdisposed within the lumen of each of the nesting links.
 16. The surgicalinstrument stabilizer system according to claim 1, wherein the preloadtensioning mechanism comprises a compression spring mounted on an anchorthat is attached to the cable.
 17. The surgical instrument stabilizersystem according to claim 16, wherein the anchor comprises a bulboushead, and the compression spring is mounted between the bulbous head ofthe anchor and a surface of the surgical instrument-supporting member.18. The surgical instrument stabilizer system according to claim 17,wherein the compression spring is biased to move the anchor and thecable away from the surface of the surgical instrument-supportingmember.
 19. The surgical instrument stabilizer system according to claim18, wherein the surgical instrument-supporting member comprises acollar, and the surface of the surgical instrument-supporting member isan internal surface of the collar.
 20. The surgical instrumentstabilizer system according to claim 19, wherein the collar isconfigured to permit rotation of the surgical instrument-supportingmember relative to the flexible arm.
 21. The surgical instrumentstabilizer system according to claim 1, further comprising a rigid armassembly that supports the articulating boom and that is attached to aside rail of a surgical table by a clamping assembly in a manner suchthat the rigid arm assembly and the articulating boom can be slid alongthe side rail.
 22. The surgical instrument stabilizer system accordingto claim 21, further comprising a locking ball coupling that connectsthe rigid arm assembly to the articulating boom, wherein the lockingball coupling carries the articulating boom at the center of gravity ofthe articulating boom.
 23. The surgical instrument stabilizer systemaccording to claim 1, further comprising a surgical instrument that issecured in the instrument-supporting member and can be repositioned andlocked in a desired position and orientation single-handedly.